%% The MIT License
%% 
%% Paralog is licensed under the MIT License.
%% 
%% Copyright (c) 2008 Robert Ahrens <mindangels@yahoo.com>
%% 
%% Permission is hereby granted, free of charge, to any person obtaining a copy
%% of this software and associated documentation files (the "Software"), to deal
%% in the Software without restriction, including without limitation the rights
%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
%% copies of the Software, and to permit persons to whom the Software is
%% furnished to do so, subject to the following conditions:
%% 
%% The above copyright notice and this permission notice shall be included in
%% all copies or substantial portions of the Software.
%% 
%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
%% THE SOFTWARE.
%% 

%% @author Robert Ahrens

Nonterminals
Elements
Fact
RuleArgs
RuleBody
Rule
Expr.

Terminals
'('
')'
','
var
atom
integer
float
':-'
'='
dot.


Rootsymbol Elements.

Elements -> '$empty' : [].
Elements -> Fact Elements : ['$1' | '$2'].
Elements -> Rule Elements : ['$1' | '$2'].


Fact -> atom '(' RuleArgs ')' dot : {fact, '$1', '$3'}. 


Rule -> atom '(' RuleArgs ')' ':-' RuleBody dot : {rule, '$1', '$3', '$6'}.


RuleArgs -> Expr : ['$1'].
RuleArgs -> Expr ',' RuleArgs : ['$1' | '$3'].


Expr -> atom : '$1'.
Expr -> var : '$1'.
Expr -> Expr '=' Expr : {unify, '$1', '$3'}.
Expr -> atom '(' RuleArgs ')' : {call, '$1', '$3'}.
Expr -> integer : '$1'.
Expr -> float : '$1'.


RuleBody -> Expr : ['$1'].
RuleBody -> Expr ',' RuleBody : ['$1' | '$3'].




